Machine for making hot tops for ingot moulds



Nov. 29, 1960 Filed Jan. 13, 1958 M. G. TIBERG ETAL 2,961,721

MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS 3 Sheets-Sheet 1 mvcmoas:MAGNUS GEORG TIBERG SVEN AXEL KJELLBERG ATT VS.

Nov. 29, 1960 M. s. TIBERG ETAL 2,961,721

MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS Filed Jan. 13. 1958 3Sheets-Sheet 2 mvau'roasz MAGNUS GEORG TIBERG BY SVEN AXEL KJELLBERG WWATTYS- Nov. 29, 1960 M. G. TIBERG Erin. 2,951,721

MACHINE FOR MAKING HOT TOPS FOR meow MOULDS Filed Jan. 13, 1958 3Sheets-Sheet 3 INVENTORS. MAGNUS GEORG TIBERG SVEN AXEL KJELLBERG Mg WATTYS.

United States Patent MACHINE FOR MAKING HOT TOPS FOR INGOT MOULDS MaguusGeorge Tiberg and Sven Axel Kjellberg, Halleors, .Sweden, assignors toAktiebolaget Svenska Kullsavgeafabriken, Goteborg, Sweden, a corporationof e en 1 :Filed Jan. 13, 19 s, Ser. No. 708,630

Claims priority, application Sweden Jan. 14, 1957 s Claims. 01. 22-49The present invention relates to a machine for making hot topsespecially those which are intended to the applied to ingot moulds formaking killed ingots. A suitable hot top may comprise a body offire-proof material, preferably fine sand, having a silicate binder suchas sodium silicate and/or potassium silicate, the sand being of suchdegree of coarseness that the body can be formed by a vibrating processwhile still being porous after drying and which has a downwardlyextending portion for projecting into the ingot mould. In the fire-proofmaterial the size of the largest grain should not exceed 5 mm. and theaverage size should be about 0.4 to 2 mm. In other words, all the grainsshould pass through a screen with ,5 mm. mesh and the greater partshould be within the limits 0.4 to 2 mm.

' The quantity of binder should be 5 to 15% by volume,

suitably about by volume of waterglass of about 38' to .40 Baumcalculated on the volume of the dry material, In the finished hot topthis will correspond to a sodium silicate or potassium silicate contentof.1.7 to 5.2% by weight calculated on the weight of the dry ma-.terial.

Thevolume of the wall of the hot top should be as small'aspossible. Itmay .thus be less than .the volume which it envelops. Excellent resultshave been obtained when the volume of the wall was 50% of the volumeenyeloped.

A hot top of this kind could be made in a core blower and hardened inthe machine in a known manner with carbonic acid, but this decreases itsstrength so that it will .not be'strong enough after drying. If the hottop is to remain intact after being moulded without carbonic acidhardening it is necessary to use a hard sand, i.e. a wet'sand. Thefinished .top will then have a tendency to crack when the steel ispoured into it and will thus be useless.

' The present invention has for its purpose to avoid these.difliculties.

, The machine according to the present invention is characterized mainlyby an outer pattern for moulding the outer surface of the hot top, aninner pattern for moulding the inner surface of the hot top, a lowerpattern for moulding its ,lower portion, said patterns togetherenclosing a space to form a mould for the hot top and being separable ina vertical direction relative each other, means for mechanically movingat least two of the said patterns in a vertical direction for closingand separating the patterns, there being a feed hopper for supplying.material to the said mould, at least one of the said patterns being"Ice connected to a vibrator for imparting vibrations thereto, means formoving the lower pattern in a substantially horizontal direction andmeans for closing olf the upper edge of the box.

The means for closing off the top may suitably be made on the principleof a camera diaphragm and have a pneumatically driven piston device forcutting off the top. It also serves to cut off the supply of mixture tothe machine. At the beginning of the next cycle the closing ofi means isopened with the aid of the same device and may suitably be locatedbetween the feed hopper and the outer pattern. The lower pattern ismovable in a substantially horizontal plane before and after themoulding operation. It is intended to mould a downward extension on thehot top for projecting down into the ingot mould and the hot top willremain resting on this part even after the operation in the machine hasbeen completed. These lower patterns may be provided with wheels and maybe movable on rails, on conveyors, carriages or in any suitable manner.

To prevent the mixture which is very sticky from adhering to the machineparts with which it comes into contact these parts are coated with asuitable material with a low coefficient of friction, e.g. polymerizedtetrafluoroethylene or, alternatively, suitably located nozzles may beprovided to spray water onto the inner and outer patterns when thelatter are in suitable positions. Still further characteristics of themachine will be apparent from the following detailed description of aform thereof.

In order to explain more clearly the manner in which the machineoperates the method of making a hot top in the machine is described inthe following with reference to the accompanying drawings in which Fig.1 shows a section through a hot top made in a machine ac cording to theinvention. Fig. 2 shows a plan view of thesame hot top. Fig. 3 shows asection through a machine according to the invention. Fig. 4 shows theclosing off means for separating the hot top from the mixture. Fig. 4-11is a fragmentary enlarged sectional plan view of the closing-oil" deviceillustrated in Fig. 4, showing the closing-01f elements retracted. Fig.4b is a fragmentary enlarged sectional plan view of the closing-0Edevice showing the closing-oil? elements advanced to cutoff position,and Fig. 5 shows the sequence of operations when making a hot top. 7

Figs. 1 and 2 show a hot top 1 applied to'an ingot mould 2; The upperpart of the mould is substantially square with rounded corners. At twoopposed sides of the mould are lugs 3. The lower part of the top isshaped to fit the mould and is extended downwards sothat an extendedportion 4 projects into the mould. Between the inner surface of themould and the outer surface of the portion 4 there will be a smallinterstice 5. This interstice is filled with a sealing substance. Thetop tapers olt upwardly and its upper part is circular. A spring 6 iswound round the top at about half its height and encircles the top 1 /2times and is extended to grip the lugs 3.

Fig. 3 is a section through a machine for making hot tops according tothe invention. The top is formed between an outer pattern 7, an innerpattern 8 and a lower pattern 9.

- The. outer pattern 7 can be raised and lowered together with a feedhopper 10 by means of a bar 11 and a pneumatically operating piston in acylinder 12. It is guided by rollers 13. A cone 14 is located within thefeed hopper 10. A discharge pipe 15 is arranged above the feed hopper 10for filling material into the hopper. The lower end of the hopper can beclosed by a cutting off device 16 which is shown more clearly in Fig. 4.The hopper may suitably be coated with polytetrafluoroethylene.

The inner pattern 8 is carried by a bar 17 and can be raised and loweredin a similar manner by means of a piston pneumatically operated in acylinder 18. A vibrator 19 is located under the pattern 8. The pattern 8is provided with a shoulder against which the cone 14 rests.

The lower pattern 9 comprises a frame member formed from a Z-shapedprofile bar and having rollers 20 for rolling on a track 21.

Fig. 4 shows the closing off device 16 which resembles the diaphragm ofa camera. It cuts off the flow of niaterial from the hopper and aftercompletion of the moulding separates the hot top from material remainingin the hopper. The closing off device comprises an outer ring 22 and aninner ring 23 which latter consists of a number of segments pivoted inthe ring 22 at 24. The closing off operation is accomplished with theaid of a pneumatic device which actuates the ring 22 through an arm- 26and a link 27. The ring is thus rotated thereby turning the segments anddecreasing the diameter of the opening to cut off the flow of material.

This closing-off device is illustrated in greater detail in Figs. 4-aand 4-1). These figures show the overlapping segments 36 pivoted on pins35 on the inner ring 23. The inner edges of the segments are formed ontwo arcs 37 and 38, respectively. When the segments are in the retractedor inoperative positions as shown in Fig. 4-0, the arcs 37 of thesegments jointly form a circle which corresponds to the inner peripheralsurface of the hopper 10, as also shown in Fig. 3.

When the segments are advanced to the operative position, as shown inFig. 4-b, the arcs 38 form a circle smaller than the aforesaid circleformed by the arcs 37, and conforming in size to the circumference ofthe upper end of the cone 8, again with reference to Fig. 3. Thus in theretracted position of the segments 36, the top of the mould cavity isopen to the hopper, and in the advanced position, the segments act toclose the opening, and in the process of advancement, to sever or toseparate the material in the mould cavity from the material in thehopper.

As previously explained, the segments are advanced and retracted byrotating an outer ring 22 through the medium of the arm 26 by action ofthe pneumatic cylinder 25, which contains a plunger connected by link 27to the arm. Each of the segments is connected to the ring 22 through themedium of a pin 24 on the ring, which is received in a slot 39 in thesegment. The inner ring is fixed through the medium of arm 41 extendinginwardly from the fixed frame of the apparatus.

Fig. shows the sequence of operations for making the hot top. A dryingfurnace is designated 28. The dried hot tops are transported from theend 29 of the furnace while resting on the lower pattern 9 which rollson wheels 20 on a track 21.

The next operation takes place at 30 where the hot top is removed andthe lower pattern is cleansed and may also be provided with a thinprotective coating of gypsum. The removal is facilitated thereby thatthe lower pattern can be opened up by means of a handle 33. The emptylower pattern is then rolled in under the machine at 31. After a new hottop has been moulded the lower pattern is transported to the furnace 28as shown at 32.

The moulding of the hot top is carried out as follows. From an elevatedcontainer (not shown) material is led through the discharge pipe 15 tofill the hopper 10 which, together with the outer pattern 7 is then inupper position. The cutting off device 16 is closed and rests againstthe cone 14. At the same time the lower pattern 9 is centered over theinner pattern 8 which is at the time in its lower position. The innerpattern 8 is then raised and the hopper 10 and the outer pattern 7 arelowered. The inner pattern 8 continues its movement until its top entersthe cone 14 after which the latter will rest on a shoulder on the innerpattern. At the end of its downward movement the outer pattern rests onthe lower pattern. The lower pattern is positioned thereby that it islocated by the inner pattern and the latter in turn is guided by thecone which is fixed to the hopper and the outer pattern. The closing offdevice is now opened and material falls quickly from the hopper into thespace formed by the inner, outer and lower patterns and the vibrator isstarted. The vibrator is allowed to run for a suitable length of timeafter the moulding space has been filled. The closing off device is nowclosed, the outer pattern raised and the inner pattern lowered, wherebythe finished hot top remains resting on the lower pattern. This istransported away, preferably direct to the furnace. The cycle isrepeated for the next hot top.

It has been found that the whole cycle takes about 20 seconds. The lowerpatterns move along a closed circular track about which furnaces arearranged. The furnace may have a capacity of for instance of about 75hot tops per hour and the operations of the machine are regulated tocoincide therewith. About 25 lower patterns will thus be required whichcirculate along the closed track through the machine and the furnaces.

The removal of hot tops from the lower pattern after they have beendried can also be accomplished automatically for instance by means of anarm with suitable gripping members, which lift the top from the patternto a suitable transporting device and the machine and the furnaces canthus be made to operate wholly automatically without special attendance.

If greater capacity is required the machine may be made with severalmoulding units working at the same time.

We claim:

1. A machine for making hot tops for ingot moulds comprising an outerpattern for moulding the outer surface of the hot top, an inner patternfor moulding the inner surface of the hot top, a lower pattern formoulding its lower portion, said patterns together enclosing anddefining therebetween a space to form a mould for the hot top and beingseparable in a vertical direction relative to each other, means formechanically moving at least two of the said patterns in a verticaldirection for closing and separating the patterns, a feed hopper forsupplying material to the said mould a vibrator connected to, at leastone of the said patterns for imparting vibrations thereto, means formoving the lower pattern in a substantially horizontal direction andmeans selectively operable for closing off the upper end of the mould.

2. A machine according to claim 1 wherein the outer pattern is movableupwards, the inner pattern is movable downwards and the lower pattern ismovable sideways from the closed position in which they together formthe mould.

3. A machine according to claim 2 wherein the closing olf device islocated between the hopper and the outer pattern. a v v 4. A machineaccording to claim 2 wherein the] inner pattern engages a conical hoodwithin the hopperwhen the inner pattern is in raised position and theouter pattern is in its lower position. Y

5. A machine according to claim 3 wherein the closing off devicecomprises an overlapping annular series of seg mental plates embracingthe upper end of the mould, and means for simultaneously adjusting theplates to close oif and to open the said upper end of the mouldselectively.

6. A machine according to claim 1 wherein the closing-off device islocated between the hopper and the outer pattern.

7. A machine according to claim 1, wherein the inner pattern engages aconical hood within the hopper when the inner pattern is in raisedposition and the outer pattern is in its lower position.

8. A machine according to claim 3 wherein the inner pattern engages aconical hood within the hopper when the inner pattern is in raisedposition and the outer pattern is in its lower position.

References Cited in the file of this patent UNITED STATES PATENTS1,698,603 Moore Jan. 8, 1929 1,911,011 Brotz May 23, 1933 2,789,332Scott Apr. 23, 1957 2,846,739 Hallsworth Aug. 12, 1958 FOREIGN PATENTS549,957 Canada Dec. 10, 1957 ERNEST w. SWIDER Attesting Officer UNITEDSTATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,961,721November 29, 1960 Magnus Georg .Tiberg et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

In the grant, line 1, and in the heading to the printed specification,line 4, name of first inventor, for "Magnus George Tiberg", eachoccurrence, read Magnus Georg Tiberg 1 Signed and sealed this 16th dayof May 1961.

(SEAL) r Attest: 1

DAVID L. LADD I Commissioner of Patents

